Android6.0 亮屏灭屏流程(DisplayPowerController、WMS)(一)WMS绘制.doc

Android6.0 亮屏灭屏流程（DisplayPowerController、WMS）（一）WMS绘制 亮屏、灭屏流程整个流程涉及的模块比较多，包括PowerManagerService、DisplayPowerControl、WMS、AMS。因此在分析完WMS之后，我们把这块也分析下。 DisplayPowerControl 我们知道灭屏流程的发起是在PowerManagerService中，会通过updatePowerState函数调用updateDisplayPowerStateLocked函数，再调用DisplayPowerControl的requestPowerState函数，到DisplayPowerControl中。DisplayPowerControl中后面会调用updatePowerState函数，我们也主要从这个函数开始分析： updatePowerState会根据PowerManagerService传过来的显示状态，然后调用animateScreenStateChange函数。 [cpp] view plain copy animateScreenStateChange(state, performScreenOffTransition); 下面我们先来看animateScreenStateChange函数： [cpp] view plain copy private void animateScreenStateChange(int target, boolean performScreenOffTransition) { // If there is already an animation in progress, dont interfere with it. if (mColorFadeOnAnimator.isStarted() || mColorFadeOffAnimator.isStarted()) { return; } // If we were in the process of turning off the screen but didnt quite // finish. Then finish up now to prevent a jarring transition back // to screen on if we skipped blocking screen on as usual. if (mPendingScreenOff target != Display.STATE_OFF) { setScreenState(Display.STATE_OFF); mPendingScreenOff = false; mPowerState.dismissColorFadeResources(); } if (target == Display.STATE_ON) {//亮屏处理 // Want screen on. The contents of the screen may not yet // be visible if the color fade has not been dismissed because // its last frame of animation is solid black. if (!setScreenState(Display.STATE_ON)) { return; // screen on blocked } if (USE_COLOR_FADE_ON_ANIMATION mPowerRequest.isBrightOrDim()) {//亮屏动画 // Perform screen on animation. if (mPowerState.getColorFadeLevel() == 1.0f) { mPowerState.dismissColorFade(); } else if (mPowerState.prepareColorFade(mContext, mColorFad